Imidazole can be used for the elution of histidine containing proteins from divalent cation resins and can also be used in reverse staining of SDS-PAGE gels for detection of proteins . Imidazole is used to elute tagged proteins bound to Ni ions attached to the surface of beads in the chromatography column. Synthetic imidazoles are present in many fungicides and antifungal, antiprotozoal, and antihypertensive medications.